SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a81f75c93d9fb1cfad08a322629b7ace2ddebf9fcf2747e3c375072654e78730' 
  AND token = 'Jtzncj2MKAwrnQ/2nowUZINHc5vgNFJmF94i2Cr/zsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}